Heart failure is a condition in which the heart is unable to pump enough blood to sustain normal bodily functions. Heart failure may affect either the right side, left side, or both sides of the heart. As pumping action is lost, blood may back up into other areas of the body, including the liver, gastrointestinal tract, and extremities (right-sided heart failure), or the lungs (left-sided heart failure). Structural or functional causes of heart failure include high blood pressure (hypertension), valvular heart disease, congenital heart diseases, cardiomyopathy, heart tumor, and other heart diseases. Precipitating factors include infections with high fever or complicated infections, use of negative inotropic drugs (such as beta-blockers and calcium channel blocker), anemia, irregular heartbeats (arrhythmias), hyperthyroidism, and kidney disease.
Implantable cardiac devices, such as pacemakers and defibrillators, monitor many different cardiac parameters that may be used to determine how well a patient's heart is functioning. For instance, implantable cardiac devices can measure morphology-related parameters, impedance, intrinsic heart rate, heart rate recovery, heart rate variability, conduction delay, pressure, posture, activity, and so forth. Each of these parameters can be used to evaluate the patient's heart.
The implantable cardiac devices are commonly configured to stimulate the heart with pulses in response to individual or combinations of these measured parameters. Additionally, the devices can store these parameters over time and periodically transmit the parameters to external diagnostic systems for more exhaustive analysis.
Unfortunately, as physicians, clinicians, and other care providers become increasingly busier with more patients to examine and less time to spend with each patient, it is often difficult to diagnose whether a patient's cardiac health is improving or deteriorating based on a cursory review of the many raw parameters collected by the implantable devices. Accordingly, there is a need to summarize the individual parameters in a way that assists the care provider quickly diagnose the patient's cardiac health. This would be particularly helpful for quickly identifying those patients whose conditions have degenerated to a point of requiring immediate attention.